William Henry Atwell

Silylene chemistry II. A kinetic study of the thermolysis of sym-dimethoxytetramethyldisilane

Abstract A detailed kinetic study of the thermolysis of sym -dimethoxytetramethyldisilane (I) has been carried out. This study provides strong support for our previous proposal that dimethyldimethoxysilane and dimethylsilylene are formed in an unimolecular and rate determining a -elimination step. Further, chemical evidence is reported which, for the first time, clearly and unambiguously demonstrates insertion of silylenes into the silicon-oxygen bond of alkoxysilanes.

Redistribution studies with organopolysilanes I. Methoxy-substituted polysilanes☆

Abstract The first detailed by study of the base-catalyzed redistribution of silicon—silicon and silicon—methoxy groups has been carried out. Subsequent to the preparation of the previously unreported series, MeO(SiMe 2 ) n OME n = 2–5), it was observed that the lower members ( n = 2 and 3) undergo a facile base-catalyzed SiSi/SiOMe redistribution. Because this redistribution involves primarily the terminal silicon—silicon bonds, this reaction offers some unique advantages in the synthesis of methoxy-substituted polydimethylsilanes.

Sultones et sultines organometalliques VII. Reactions d'insertion de l'anhydride sulfureux dans la liaison silicium-carbone: Sultines organosiliciques

Abstract The behaviour of some substituted silacyclobutanes with respect to sulfur dioxide is studied. The alkylated, arylated and alkoxylated derivatives of silacyclobutane react with SO 2 to give the first “silasultines” (2-oxo-4-sila-1,2-oxathianes). The structure and the configurational analysis of the insertion products are proved by chemical and physicochemical ways. The mechanism of the SO 2 insertion is discussed.

Silicon Carbide Preceramic Polymers as Binders for Ceramic Powders

While a variety of organosilicon polymers have been prepared over the years as precursors to silicon carbide ceramics, only a few have been used with silicon carbide powders in traditional ceramic processing. Of these polymer systems none have the design flexibility to allow for their use with ceramic powders over a range of polymer levels. For example, polycarbosilane has both a fixed polymer rheology and ceramic composition. Some of the focus within the Dow Corning Advanced Ceramics Program has been to develop a family of preceramic polymers that in combination with ceramic powders are useful for the preparation of monolithic ceramics. This paper describes the development of polymers that provide specific ceramic compositions and controlled rheologies making them useful as polymeric ceramic binders. A discussion of the polymer families developed, their physical and ceramic properties, the ceramic processing employed (die pressing, isopressing, injection molding, etc.) and some of the properties of the resulting ceramics is presented.